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Biomedical subjects

J M Jones

Publications and source records attributed to J M Jones.

At least 325 records · Page 18Linked to original sources
PubMed1972

Thio reduction of human 2 -macroglobulin. The subunit structure.

1. Human alpha(2)-macroglobulin was prepared from a fraction obtained during the large-scale separation of normal human plasma proteins for clinical use. 2. Sedimentation-equilibrium measurements indicated a molecular weight of 725000. A value of 18.1S was obtained for s(0) (20,w). 3. The dissociation that occurs in the pH range 4.5-2.5 and in the region of neutrality in urea-containing solutions is consistent with a dimeric structure of the molecule. 4. The effects of the thiol reagents mercaptoethanol, mercaptoethylamine and N-acetylcysteine were investigated over a range of experimental conditions. Distinct components having sedimentation coefficients of 15, 12 and 8.5S were identified. 5. Conditions were found under which limited reduction with thiol liberated a subunit with a molecular weight approximately one-quarter of that of the intact molecule. This subunit retains the serological specificity of the whole molecule.

Acetylcysteine↗
PubMed1970

Effects of streptococcal cell wall fragments on phagocytosis and tissue culture cells.

Group A streptococcal cell wall fragments inhibited phagocytosis of unrelated particles by rabbit polymorphonuclear leukocytes and inhibited the growth of rabbit kidney cells in vitro. Activity was associated with the mucopeptide moiety. Whole streptococci or the cytoplasmic fraction were less effective than cell wall fragments. The cell wall fragments of group D streptococci, Bacillus megaterium, and Escherichia coli were inactive. The inhibition of phagocytosis illustrates one way in which microbial components may influence the immune response. The toxicity for tissue cultures of rabbit kidney cell monolayers was greatest during the phase of active cell division. This appears to be a direct toxic effect of cell wall fragments on mammalian cells and may be related to the in vivo injury previously reported for streptococcal cell walls.

Journal Article↗